Abstract: A heat transfer media that provides more complete and more even use of the media volume by enhancing the characteristics and/or directions of fluid flow across the media. The heat transfer media includes a heat transfer block having one or more layers that include longitudinal flow passages for enabling fluid flow in the longitudinal direction across each layer, and also include transverse flow passage for enabling lateral cross-flow between the longitudinal flow passages. The heat transfer block may include a plurality of stackable plates, with each plate having fins laterally spaced apart to define longitudinally extending channels, and at least one aperture extending transversely through at least one fin for enabling transverse cross-flow between the longitudinal channels. The aperture may be configured as a recessed groove in the fin, and the fin may have ridge portions longitudinally spaced apart to at least partially define the recessed groove.